Johnny Raper, the highly resilient and persistent lock-forward commenced his professional rugby league career at Newtown during his teenage years in the latter part of the 1950s. He swiftly became an integral and indispensable member of the St George team, which achieved an extraordinary and unprecedented feat by securing 11 consecutive premiership trophies from 1956 to 1966. And the colourful ‘Chook’ is perhaps as famous for his personality off the field as his deeds on it, including a folkloric tale about a nude stroll down an English street wearing nothing but a bowler hat.

Raper was born in Camperdown and grew up in Revesby south-western Sydney in a working-class family with nine boys. He played his junior rugby league for the Camperdown Dragons before representing Newtown's President's Cup side in 1956. Raper joined and made his first grade debut for Newtown in 1957 as an eighteen-year-old. Despite becoming a much lauded lock forward, in his 1957 debut season with the Newtown “Bluebags” (as the team was known then) Raper played in the second row in all of his first grade appearances except one when he played at five-eighth.

In 1959 Raper joined St George as a lock forward and in this position he became an international rugby league star. His legendary cover defence and ball skills saw him acknowledged during his playing career as the best loose-forward the world had ever seen. He played in eight Grand final wins with St George between 1959 and 1966. Raper attributed his success to a training discipline and fitness fanaticism that was ahead of its time. While St George's early adoption of circuit training in the late 1950s was a major contributing factor in their eleven-year premiership run, Raper's own commitment to additional running and weights every day and often alone, enabled him to achieve a personal goal of being the fittest player in the fittest team in the competition.

Raper's last season with St. George was in 1969 as captain-coach. In 1969 he appeared as a guest player for Auckland in a match against the New Zealand national rugby league team to mark the New Zealand Rugby League's diamond jubilee. Raper was awarded Life Membership of the St. George Dragons Club in 1971. Raper played three seasons with the Western Suburbs Rosellas in the Newcastle competition from 1970 to 1972. He captain coached the club and took them to victory in the 1970 grand final. He finished his playing career with Kurri Kurri from 1973 to 1974. In 1959–60 he made the first of his three Kangaroo tours, scoring a try on debut in the third Test loss vs Great Britain at Wigan. For the next ten years he was rarely, except for injury, out of the Australian Test team.

Raper returned to Sydney as coach of the Cronulla-Sutherland Sharks in 1975 and 1976, commencing an association with that club later carried on by his sons Stuart and Aaron. He also coached a Lane Cove Rugby Union Club team to victory in the Judd Cup suburban competition in 1977.